Three insoluble enzymes (cellulase, phosphatase and urease) were found
in the sediment phase of the Venice lagoon within an area of shallow
water, the Palude della Rosa. Several washing treatments were performe
d to evaluate the binding forces between the enzymes and the solid pha
se. Urease was strongly bound and unaffected by all washing procedures
tested, whereas phosphatase and part of the cellulase could be remove
d by phosphate anions. Cellulase activity was also solubilized by a no
n-ionic detergent. These immobilized enzymes showed marked heat stabil
ity and an increased resistance to environmental changes. They were pr
obably of bacterial origin and could be advantageous for the removal o
f specific substances from water. They could be useful as diagnostic f
actors of the ecosystem, since their presence is related to the waste
products and their lifespan is prolonged by their insolubilization.